1. Field of the Invention
The present invention relates generally to a static random-access memory (SRAM) cell array and forming method thereof, and more specifically to a SRAM cell array applying dummy fins and forming method thereof.
2. Description of the Prior Art
Random access memory (RAM) can be operated to read data from it and write data into it. As the computers turn off, data disappears immediately. Since data in RAM can be altered easily, RAM is widely used as temporary data storage memory in personal computers. RAM can be classified into dynamic-type and static-type.
A dynamic random access memory (DRAM: Dynamic RAM) stores one-bit data by one transistor paired with one capacitor, and electricity must be supported during operating to keep this data, thus called Dynamic RAM. Dynamic RAM is a simple structure, therefore having slow access speed and costing low. Thus, it is often used as a memory providing high capacity but low speed such as a main memory of a personal computer.
A static random access memory (SRAM: Static RAM) stores one-bit data by six transistors, and electricity is not needed during operating to keep this data, thus called Static RAM. Static RAM is a complex structure, therefore having high access speed and costing high, thereby it is often used as a memory providing low capacity but high speed such as a 256 KB or 512 KB cache memory built-in a central processing unit (CPU) of a personal computer. Since a CPU mainly affects data calculating and processing speed of a computer while a main memory mainly affects data storage capacity, a cache memory is utilized to save often-used data, thereby the CPU can more quickly reach this often-used data stored in the cache memory, without reaching it in the main memory.